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COVID-19 Testing: Joint letter from Teton County Health Department and St. John's Health

14-Apr-2020

Dear Community Members,

We want to respond to the questions that many of you have asked about COVID-19 testing in Teton County, WY.

There are two types of COVID-19 testing. The first is active disease testing and the second is antibody testing. These two types of tests, ideally, may be used together to develop an overall picture of COVID-19 in our community. Active disease testing identifies individuals who need to be isolated or quarantined and can be used with isolation and contact tracing to control spread of the disease in our community. Information about whether a patient has COVID-19 also helps healthcare providers make medical decisions and take other steps to keep patients and healthcare workers safe. We know for certain that active disease testing is very appropriate and necessary based on the current phase of the disease curve in Teton County. Because antibody testing may also provide valuable information, St. John’s has asked a group of local physicians, scientists, and experts to review and advise us on currently available antibody testing platforms that may be valuable to our community. St. John’s has stated that it will base decisions about antibody testing for healthcare workers and emergency responders on the recommendations of this group.

First, it is important to distinguish between active disease testing and antibody testing.

Active Disease Testing is used to identify if a person has COVID-19 on the day the person is tested. The current COVID-19 case counts being reported across the globe, and in Teton County, are from this type of testing. This test result will be negative if a person does not have COVID-19 at the time the test was taken, even if they have previously had COVID-19. The test is conducted by taking a nasopharyngeal swab to test a person’s upper respiratory tract specimen. The swab is then sent to either the Wyoming Public Health Laboratory or a private lab for testing. All the laboratories used by Teton County, Wyoming providers are authorized by the Food and Drug Administration (FDA) under an Emergency Use Authorization (EUA) to conduct Real-Time reverse transcription polymerase chain reaction (RT-PCR) to test the samples submitted. Real-Time RT-PCR test is a qualitative test that detects nucleic acid from SARS-CoV-2 (the virus that causes COVID-19) in the nasopharyngeal swab submitted by healthcare providers.

Antibody Testing determines if a person has developed antibodies to COVID-19. Antibodies form in response to being exposed to COVID-19. However, after exposure to COVID-19, there is a delay in the formation of antibodies in a person. An antibody test (serology immunoglobulin test) for COVID-19 tests an individual’s serum, blood, plasma or finger prick sample for the presence of IgM or IgG. A positive test result would indicate that a person has previously been exposed to COVID-19 and has developed an immune response. It is important to note that current antibody testing may not be a reliable way to identify persons who are currently infected with COVID-19. Positive antibody tests may be due to present or past infections with a non-SARS-CoV-2 coronavirus due to cross-reactivity with other common non-COVID-19 human coronaviruses. Similarly, a negative antibody test does not rule out a SARS-CoV-2 infection because a person could be presymptomatic, in the early stages of their illness, or immunocompromised. Currently, there is only one FDA -approved antibody test on the market. Right now, these tests are not known to confirm immunity, measure the strength of one’s immunity or determine how long immunity might last. The FDA has also warned against fraudulent test kits that are being sold. The hope that we hold for this type of testing is that it may provide a better understanding of the spread of COVID-19 along with calculating accurate case fatality rates and developing other important indicators. Antibody testing may also prove useful for identifying first responders, medical providers and others who have been exposed and who can safely resume work without needed to be quarantined or isolated.

To assess testing platforms and the value of antibody testing for Teton County, Dr. Beaupre has selected a panel of local experts who have backgrounds in medicine, public health, scientific research, biotechnology, laboratory science, and biostatistical and epidemiological data. In addition to their professional qualifications, these individuals have no financial interests in companies currently offering antibody testing. Dr. Beaupre and Jodie Pond will participate in the group’s sessions but will not participate in voting on a recommendation. The members of the panel are: Dr. Travis Riddell, Dr. Marcia Lux, Dr. Jim Little, Dr. Jeff Greenbaum, Dr. Lars Conway, Dr. Marc Domsky, Matt Lenz, Zach Hall, Laurentius Marais, and Chuck Fleischman.

Until there is a reliable antibody test, we feel strongly that we should continue first and foremost to direct available financial and human resources into doing more widespread COVID-19 active disease testing so that we can more quickly stop the spread of COVID-19 in our community.

It is the opinion of the Teton District Health Officer, the CEO of St. John’s Health, the Director of Teton County Health Department and other public health experts that antibody testing should not be the focus of the current effort to control the spread of COVID-19, but that we should conduct a robust exploration of whether antibody testing may soon be an important part of our public health response to this disease.